The U.S. and Mexico will commit to joining Canada in boosting their use of wind, solar and other carbon-free sources of electricity, helping North America meet an ambitious goal of generating at least 50 percent of its energy from “clean” sources by 2025.

The pledge is set to be made as part of a trilateral summit of North American leaders Wednesday in Ottawa, where the U.K.’s decision to leave the European Union is likely to consume much of the agenda. The meeting will also focus on trade and regional security issues.

“We believe this is an aggressive goal but one that is achievable by all three countries,” Brian Deese, a senior adviser to President Barack Obama on environmental and energy matters, said Monday on a conference call with reporters.

The goal applies across the continent, meaning it’s an average for Canada, Mexico and the U.S. together. The goal, which would need to be adhered to by the president who succeeds Obama in January, is “achievable if all three countries respectively make ambitious progress toward executing and in effect exceeding the targets” established in the climate accord reached in Paris last year, Deese said.

The commitment will apply to any electricity generated without producing carbon dioxide emissions, including nuclear as well as renewable wind, solar and hydro power. Deese said it also could apply to power from plants using carbon-capture technology to siphon off emissions. The goal does not otherwise include natural gas, which burns cleaner than coal but still produces carbon dioxide emissions that contribute to climate change.